Fast Synthesis of High-Molecular-Weight Polyglycolide Using Diphenyl Bismuth Bromide as Catalyst

Biodegradable polymers are frequently obtained from ring-opening polymerizations (ROPs). Applications in the biomedical sector require medical-grade materials free of any toxic residues, as well as polymers with well-defined properties. Thus, the selection of nontoxic catalysts for ROP, which allow for well-controlled molecular weights, is very important. In this contribution, ROPs of diglycolide are reported by using diphenyl bismuth bromide as catalyst. The reactions are carried out in bulk at temperatures ranging from 130 to 150 °C. The number-average molecular weights are in the range of 20–250 kg mol⁻¹ depending on the reaction temperature and time, as well as the catalyst concentration. The reaction times required to yield diglycolide conversions exceeding 95% are in the range of minutes. The thermal properties such as melting and crystallization temperatures are independent of polymer molecular weight.